If you rank the Hulls, Bobby Hull is by far the greatest of them all, but his son Brett is a pretty close second. Dennis the little brother of Bobby would be the third greatest Hull to play in the NHL, and he had a very solid NHL career all with the Blackhawks.
Dennis Hull made it to the Chicago Blackhawks roster at the age of 20 in 1964 and after a couple of years finally started playing pretty good hockey. He was a 4 time 30 goal scorer throughout his career and he hit 40 once, but he always played under the cover of the Bobby Hull shadow.